ASTM F879-12 - 1.6.2012
 
1. Scope

1.1 This specification covers the chemical and mechanical requirements for stainless steel inch hexagon socket button (SBHCS) and flat countersunk (SFHCS) head cap screws with nominal thread 0.060 through 0.625 in. intended for use in applications requiring general corrosion resistance.

1.2 Two groups of austenitic stainless steel alloys and three conditions are covered. See Table 1 and Table 2.

TABLE 1 Mechanical Property Requirements

Alloy Group

Alloy
Condition

Full Size Product TestsA

Machined Specimen Tests

Core HardnessB

Tensile
Strength ksi

ExtensionC
min

Tensile
Strength ksi

Yield
Strength ksi

Elongation
% min

Vickers

Rockwell

All

   AF

   85 max

0.6D

   85 max

55 max

40

210 max

95 HRB max

All

   CW

   80 min

0.4D

   80 min

40 min

25

150 min

50 HRA min

All

   CW1

  102 min

0.4D

   87 min

65 min

20

220 min

59 HRA min

A Actual full-size testing of condition CW and CW1 may result in decreased tensile strength because of the head configuration (see Table 3). For fasteners with nominal thread diameters larger than 0.625 in., the mechanical properties shall be agreed upon between the user and manufacturer.
B Core hardness is only required when full-size product testing cannot be accomplished.
CD denotes nominal thread size.
TABLE 2 Chemical Requirements

Alloy Group

UNS Designation

Alloy

Composition, % maximum except as shown

Carbon

Manganese

Phosphorus

Sulfur

Silicon

Chromium

Nickel

Copper

Molybdeneunm

Austenitic Alloys

1

S30400

304 

0.08

2.00

0.045

0.030

1.00

18.0 to 20.0

 8.0 to 10.5

1.00

. . .

1

S30403

304L

0.030

2.00

0.045

0.030

1.00

18.0 to 20.0

 8.0 to 12.0

1.00

. . .

1

S30500

305 

0.12

2.00

0.045

0.030

1.00

17.0 to 19.0

10.5 to 13.0

1.00

. . .

1

S38400

384 

0.08

2.00

0.045

0.030

1.00

15.0 to 17.0

17.0 to 19.0

. . .

. . .

1

S30430

18–9LW 

0.10

2.00

0.045

0.030

1.00

17.0 to 19.0

 8.0 to 10.0

3.0 to 4.0

. . .

1

S30433

302HQ

0.03

2.00

0.045

0.030

1.00

17.0 to 19.0

 8.0 to 10.0

3.0 to 4.0

. . .

2

S31600

316 

0.08

2.00

0.045

0.030

1.00

16.0 to 18.0

10.0 to 14.0

. . .

2.00 to 3.0

2

S31603

316L

0.03

2.00

0.045

0.030

1.00

16.0 to 18.0

10.0 to 14.0

. . .

2.00 to 3.0


1.3 Units—The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 The following precautionary caveat pertains only to the test method portion, Section 12, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

 
2. Referenced Documents

E92-23

Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials

E18-22

Standard Test Methods for Rockwell Hardness of Metallic Materials

F593-22

Standard Specification for Stainless Steel Bolts, Hex Cap Screws, and Studs

F606/F606M-21

Standard Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets

F788-20

Standard Specification for Surface Discontinuities of Bolts, Screws, Studs, and Rivets, Inch and Metric Series

F1470-24

Standard Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection

B18.3

Socket Cap, Shoulder and Set Screws (Inch Series) Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://www.asme.org.

JIS G 4309

Stainless Steel Wires

A262-15(2021)

Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels

A342/A342M-21

Standard Test Methods for Permeability of Weakly Magnetic Materials

A380/A380M-17

Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems

A555/A555M-23

Standard Specification for General Requirements for Stainless Steel Wire and Wire Rods

A751-21

Standard Test Methods and Practices for Chemical Analysis of Steel Products

A967/A967M-17

Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts

D3951-18(2023)

Standard Practice for Commercial Packaging

E384-22

Standard Test Method for Microindentation Hardness of Materials